LOS ANGELES — Dogs and cats have become part of the American family inner circle over the last 20 years, sleeping in their own beds or yours, eating food bought specially to help their digestive tracts, drinking purified water and cuddling up in chairs on heated pads made to fend off arthritis.

Some pets have their own vets, groomers, trainers, sitters and occasional walkers. All this suggests a bright future for an industry that has grown alongside the popularity of pets, expanding at a steady 4 to 6 percent a year since the American Pet Products Association started record-keeping in 1996.

Americans spent an all-time high $55.7 billion on their pets last year and spending will creep close to $60 billion this year, association president and CEO Bob Vetere told buyers and exhibitors at the Global Pet Expo in Orlando, Fla., on Thursday.

The biggest chunk of spending in 2013 — $21.6 billion — went for food — a lot of it more expensive, more healthful grub. In 1996, total pet spending was just $21 billion. Adjusted for inflation, that’s $31.3 billion.

The humanization of our pets started about 20 years ago, Vetere said in a telephone interview. As pets accepted their new perch in the family, manufacturers introduced products that helped animals move from the backyard to the front room.

“What is feeding a large part of the growth now are the baby boomers who have become empty-nesters and are looking for some other ways to find the love and affection they used to get from their kids,” Vetere said.

“In the past, children were a reflection of us and people are now extending that to their pets,” said Dr. Jessica Vogelsang, a San Diego veterinarian. People don’t just bring their pets in for health reasons anymore — they also want them to look good and smell good, she said. “From my perspective, it’s a good thing. It’s nice to see people care as deeply as they do.”

Follows human trends

People have always spent more on food than any other pet-spending category and pet-food trends follow human food and diet trends, according to Vetere.

That means if you are on a health kick, chances are your pet is too.

“Food choices are extraordinarily confusing,” Vogelsang said. “I think people spend more time in the dog-food aisle than they do in the rest of the store.”

Dave Bolen is president and CEO of Pet Supplies Plus, a chain of 294 specialty stores in 24 eastern states. His 25-year-old business has expanded every year — it opened eight stores in 2013 and plans to open 30 this year.

“We are bullish about pet ownership,” he said.

It can only get better, Bolen added, as people discover all the healthy benefits of owning pets.

Other spending last year included $14.4 billion for veterinary care; $13.1 billion for supplies and over-the-counter medicines; $2.2 billion for live animal purchases; and $4.4 billion for other services.

Those services include grooming, boarding, training and pet-sitting and grew by the largest percentage last year — 6.1 percent.

American pets include an estimated 95.6 million cats and 83.3 million dogs, the American Pet Products Association said. There are also 20.6 million birds, 8.3 million horses, 145 million freshwater fish, 13.6 million saltwater fish, 11.6 million reptiles and 18.1 million small animals.